1. Field of the Invention
The present invention is directed to a centrifuge tube and to a specimen collection assembly comprising same, such as may be usefully employed for collection of forensic evidence at crime scenes, collection of site samples at sites suspected of contamination with bioterrorism agents, or the like.
2. Description of the Related Art
Centrifuge tubes of widely varying type have been employed for centrifugal separation of specimen samples to isolate components thereof, such as by inserting a collected specimen in the centrifuge tube and adding a wash or elution medium thereto, followed by centrifugation processing, to produce a supernatent liquid and pelleted solids. Alternatively, the wash or elution medium can be added to the centrifuge tube prior to introduction of the collected specimen thereto. In either event, the centrifugation processing produces supernatent and pelleted solids, which can then be separated from each other, e.g., by decanting of the supernatent liquid from the compacted solids mass in the lower end of the centrifuge tube.
Centrifuge tubes of such type are utilized in a wide variety of applications, including collection of forensic evidence at crime scenes, sample collection at suspected bioterrorism sites, collection of chemical contaminants at industrial accident sites, etc.
Frequently, the specimen to be processed in the centrifuge tube is collected by means of a swab including a stick, wand or other elongate member having mounted at its distal end a sorptive or adherent pad for collection of fluid and/or solid samples, for subsequent processing and analysis.
In some instances, the swab element at the distal end of the swab article is sufficiently porous, permeable or adherent so that it is difficult to transfer the collected specimen in its entirety from the swab matrix into the liquid that is added to the tube for centrifugation. Further, the swab element in contacting the liquid in the centrifuge tube for transfer of the specimen will take up the liquid so that when the swab is withdrawn from the centrifuge tube after contacting the liquid therein, the swab element will retain liquid and such liquid in many instances will retain specimen. The retained liquid therefore may significantly reduce the amount of collected sample that is transferred into the liquid in the centrifuge tube, thereby reducing the efficiency and accuracy of the specimen work-up.
Among the centrifuge tubes that have been proposed by the prior art are the tube articles disclosed in: U.S. Pat. No. 3,977,598 issued Aug. 1, 1976 to Bernard McDonald; U.S. Pat. No. 5,859,374 issued Jan. 12, 1999 to Mink et al.; U.S. Pat. No. 4,552,278 issued Nov. 12, 1985 to William A. Romanauskas; U.S. Pat. No. 4,511,349 issued Apr. 16, 1985 to Steven P. Nielson, et al.; and U.S. Pat. No. 4,512,202 issued Apr. 23, 1985 to Herschel E. Wright, et al.
The art therefore is in need of an improved centrifuge tube that permits improved extraction of specimen from a swab element, without substantially increasing the cost or complexity of the tube relative to currently employed tube structures.